Grinder attachment



June 21, 1955 J R, HlLDRE'TH 2,711,055

GRINDER `ATTACm1ENT Filed Feb. 17, 1954 United States Patent The present invention relates to grinders for sharpening shears, scissors, and the like, `andparticularly to those grinders which are adapted to be removably secured to a parent grinding machine, that specialized grinding jobs may be performed.

Heretofore grinders for specialized grinding operations 1i cording to the needs of the operator.

have been available only as separate and costly pieces of l f equipment or as complex and costly attachments. Many of the known types are of bulky or impractical construction, or they. fail to provide proper safeguards for the operator. Others are too-frail to provide lasting service, while still others, which employ a part of the parent grinding device to actuate its grinding member, cause Wear on l its own as well as the parent machine part or parts, thereby requiring a halt in use of the combination until adjustments or compensation can be made for the worn parts, or they are replaced. In this last-mentioned type of grinders all compensations or adjustments are made by hand and require the machine to be stopped detracting from its efciency. In addition many of the devices of the prior art fail to provide adjustable rests for the tools to be sharpended or provide adjustable rests which are insecure and actually adjustable only with great diiculty.

Therefore among the objects of the present invention is to provide a grinder for specialized grinding operations, as an attachment for a parent machine, which is .of relatively simple but sturdy manufacture, and one which provides lasting service and proper safeguards for the operator. A further object is to provide a grinder attachment for a parent device in which a part of the parent device is used to actuate the grinding member of the attachment and in which when the part or parts of the attachment and the parent device adjust or compensate for wear automatically without requiring the machine to be stopped until replacement is necessary. A still further object is to provide a grinder as an attachment, which is provided with a rest for the tool or instrument to be sharpended and which may be securely locked in position and yet easily adjusted to meet the needs of the operator. These and further objects and advantages will appear evident as the disclosure continues.

According to the present invention, a grinder attachment which is adapted to be secured to a parent machine having a rotatable wheel thereon is provided, in which the grinding wheel of the attachment is rotatably positioned inv a frame, so that when the frame is in the operative position said wheel is above the rotatable wheel of the parent device, and in which the two Wheels are separated by an idler wheel having a periphery which frictionally engages each of the other two. Thus when the wheel of the parent machine is caused to rotate the grinding wheel of the attachment is also caused to rotate through the medium of the intermediate idler wheel. The three wheels are preferably directly over one another or in substantially vertical alignment. The center of the three Wheels, i. e. the idler or the contact wheel, is so mounted in the frame as to automatically adjust or compensate for Wear of the wheels, thereby maintaining a smooth continuous grinding action. i

j i 2,711,058 A,- Patented June 21,19575l ice Secured to the. attachment in such a manner as to be immediately adjacent the periphery of the grinding wheel, is an adjustable rest, which is pivotally and adjustably mounted to the frame structure in such a manner as to provide for easy and accurate adjustment of the rest table ac- While some of the more salient features, characteristics and advantages of the instant invention have been pointed out above, others will become apparent from the following disclosure taken in conjunction with the accompanying drawing of a preferred embodiment of which Fig. l is a top view of the grinder;

Fig. 2 is a side view of the grinder attached to a parent machine, the latter being designated by brokenlines;

Fig. 3 is a front View of the grinder attached to the parent machine which `is designated by broken lines; and

Fig. 4 is a cross-section taken along the line 4-4 of Fig. 2. f i

In the illustrationtheparent machine comprises a frame v F having a top surface S"upon which the grinding attachment may bemounted, the machine having a driven grinding wheel W which-'projects above the surface Sfinto a notchV N inthe top ofthe frame. i'

The attachment of the present invention comprises a base 1 for attachment to the surface S by means of a screw 2 and a housing 3 pivotally mounted on the base 1 by means of a bolt 4, the housing being U-shaped in crosssection as shown in Fig. 3 and having a V-shaped opening 6 at the front (Fig. 2). Rotatably mounted in the housing by means of a bearing 7 is a grinding Wheel 8. Below the wheel 8 an idler wheel 9 is mounted in slots 11 by means of bearings 12 which have outer ends of reduced diameter slidable in the slots.

Pivotally mounted at 13 is a tool rest comprising sides 1d and a top 16. The sides 14 have slots 17 to receive al pin 18 having a knurled head 19 at one end. Threaded on the other end is a knurled nut 21. By loosening nut 21 the rest may be adjusted to different positions depending upon the character of the tool to be sharpened.

From the foregoing it will be evident that the three wheels 8, 9 and W are held in peripheral contact by the wheels are not in any way critical and would be variable with the requirements of diierent jobs. The only limitation is that the surface of the intermediate idler Wheel should frictionally engage the peripheries of the Wheels above and below it.

In addition it should be further emphasized that the grinder may be attached wherever there is a rotatable wheel or roll, and a means to drive them. It is of course obvious that the device will iind its greatest application in being adapted to grinding machines.

lt should be understood that the present disclosure is for the purpose of illustration only, and that the invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim: f

l. A tool sharpening attachment for a parent device having a rotatable grinding wheel thereon, said attachment comprising a frame, means for pivotally attaching said frame to the device, a grinding wheel so positioned in said frame as to be above the grinding wheel of the device, an adjustably mounted idler wheel having a frictional surface contacting both vof said wheels, whereby y when the grinding wheel of the parent device is rotated, it causes the idler Wheel andu the grinding wheel of the attachment to rotate, an adjustable rest adjacent to the periphery of 'the vgrinding wheel-,.ofzthe attachmen't,.the side o'f `said 'restibeing 'pivotally 'mounted on the sides of the frame, said rest 'being adjustal'aleV through the .length of parallel slots in said sides, rand means for locking said rest ata` selected position. Y

2. A tool sharpening .attachment for Va .grinding machine having a rotatable ,grinding wheel thereon, said attachment cdmprisingy a housing, means for pivotally attaching said housing to the grindngmachine, a grinding wheel rotatably mounted inside of said housing and above the grinding wheel of the grinding 1machine,ia selfadjusting rubber covered idler Wheel having an axially positioned shaft therein between said grinding wheels, parallelelongate slotsin the -sides ozthe grinder housing in which the shaft of the :idler wheel may move up and down, andan adjustable rest -pivotally mounted on said housing.

3. A tool sharpening attachment for a parent device having a wheel thereon, .said attachment comprising a frame, a grinding Wheelso Apositioned in said frame as to be above the wheel of the device, an idler Wheel having a frictional surface contacting bothv of said wheels so that, when the wheel of the .parent v'device is rotated, it

causes the idler wheel and the grinding wheel to rotate,

means for movably mounting the frame on said deviceV f so that the Wheels are held ,in Contact by gravity, and means for supporting the idler wheel on the frame so that it is freely movable toward the grinding Wheel to compensate for Wear automatically. -f

4. For attachment to a machine having a frame anda` the projecting wheel, an idler Wheel rotatably mountedlin the housing between the other two Wheels, whereby the Weight of the housing and parts carried thereby holds the three Wheels in peripheral Contact, and means for supporting the idler Wheel on the frame so that it is freely movable toward the grinding wheel to compensate for wear automatically.

References Cited in the tile of .patent UNITED STATES' PATENTS 504,329 n 1,185,182 Davis May 30, 1916k Clapp Sept. 5, 1893 v p Greenaniyer l Apr. 3, 1917 i 

